White field chromaticity coordinates displayed by current display devices such as a liquid crystal display device, plasma display device and rear projection display device and the like are different from each other more or less due to the discrepancies among the displaying principles or hardware designs thereof. If a corresponding white balance adjustment is not executed to the white field chromaticity coordinate discrepancies of the display devices, there will be significant differences in the color display effect among different display devices. Accordingly, white balance tracing and corrections are usually executed during the manufacturing process of the display devices so that a color displayed by the respective display devices tends to be consistent.
Generally, the white balance tracing and correction technique is to make a white point mixed by three primary colors RGB of each gray level satisfy Wxn=Wx255, Wyn=Wy255, n=1.2 . . . 255 (where Wx and Wy are chroma values of CIE1931 chromaticity coordinate system, n is the gray level number) by setting spectral tristimulus values of the three primary colors RGB (i.e. red, green, blue) corresponding to each gray level. However, CIE1931 chromaticity coordinate system utilizes non-uniform color space coordinates and fails to reflect the stimulation of brightness to human eyes. The requirements of Wxn=Wx255, Wyn=Wy255, n=1.2 . . . 255 in CIE1931 chromaticity coordinate system fails to reach the requirement that the human eyes feel the brightness change while the same hue and saturation are maintained at the same time, so that it fails to make the human eyes feel the same chromatic stimulus.
Therefore, there is a need for a white balance adjustment method to solve the problem existing in the prior art.